During the process of cataractogenesis one often sees the partial breakdown of lens structural proteins. The cataractous lens contains enzymes which degrade protein, RNA and DNA, however these cannot be demonstrated in normal lens tissue. We feel that this is due to the fact that these degradative enzymes are inhibited in the normal lens. We have demonstrated the presence of a RNase, DNase and trypsin inhibitor in the normal lens. Purification of the RNase inhibitor and trypsin inhibitor have been achieved. We intend to continue these studies in order to obtain pure DNase inhibitor as well. We propose to study the properties of these inhibitors to determine how these inhibitors are inactivated during cataract formation. Sensitivity to conditions and reagents which have been implicated in cataract formation will be measured. In addition the state of these proteins will be measured in cataractous lenses to determine the mechanism of inactivation.